While the histogram is potentially useful and is easy to work with, I'm finding its lack of being able to handle calculated metrics and/or segments applied just to the visualization pretty limiting in how I'd want to use it. For example, I may just want to see portions of the site, certain types of devices, certain products.
I did find that you can have a segment on the panel and the histogram seems to apply something. However, there are many cases where you wouldn't want that segment applied to your other tables so this isn't a great solution either (you'd have to have your histograms in a separate panel). I'm also not 100% sure how it is handling these segments. For example, I have a hit segment applied that looks at one specific page on my site that does not have any file downloads. However, if I look at a histogram for file downloads, I see data there. Is this looking at files downloaded by anybody who had hit that page in their visit (or visitor level depending on your counting method setting)?